| SOI (Silicon on insulator) as a kind of irradiation hardness starting material has been widely used in areas of defense and space navigation. But due to an insulating layer in its structure, the tolerance of total dose irradiation of SOI is poorer than normal silicon material. Several ways have been studied to harden the SOI devices.To deal with this problem, we put a new SOIM structure forward as a candidate.Co-implantation of oxygen and nitrogen ions into silicon and post-annealing has been carried out to prepare a new Si/Si-N-O/Si3N4/Si SOIM structure. The up-interface between top silicon and buried layer in this structure is also improved. Meanwhile XTEM, SIMS and Spreading resistance have been adopted to characterize the structure and the electrics quality. It was found that impurities diffuse to the interface during annealing process causing local enrichment of the elements.The advanced IRIS program was used to simulate the above process. And the result of simulation is accordance with the measured results.The C-V curses of Bounding etch-back SOI, Low-dose SOI and SOIM prepared according to above art were measured before and after irradiation. And P MOSFETs were fabricated on above materials. The threshold voltages of above devices were measured before and after irradiation. The mechanism of total dose effects has been discussed in this thesis. The tolerance of total dose effects of these materials was evaluated. It could be concluded that the hardness to the total dose irradiation of SOIM is significantly superior to that of Bonding Etch-back SOI and Low-dose SOI.We also used fractal to analysis the rough up-interface between top silicon and buried lay in SIMOX-SOI. It was founded that the up cut-off length of Si/SiO2 in thermal oxide silicon is longer than it in SIMOX-SOI. We took a hypothesis to explain the phenomena. We hope it can benefit the further understanding of the forming of interface between silicon and buried layer in SIMOX. |
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